The word(s) "believer" appears 309 time(s) in 259 verse(s) in Quran in Abdullah Yusuf Ali translation.

(221) But teach (thy Message) for teaching benefits the believers.

(222) Woe, then, to the Unbelievers, on account of that Day of theirs which they have been promised!

(223) Hastening, with eyes transfixed, towards the Caller!- "Hard is this Day!", the Unbelievers will say.

(224) Are your Unbelievers, (O Quraish), better than they? Or have ye an immunity in the Sacred Books?

(225) One Day will the Hypocrites- men and women - say to the believers: "Wait for us! Let us borrow (a Light) from your Light!" It will be said: "Turn ye back to your rear! then seek a Light (where ye can)!" So a wall will be put up betwixt them, with a gate therein. Within it will be Mercy throughout, and without it, all alongside, will be (Wrath and) Punishment!

(226) Has not the Time arrived for the believers that their hearts in all humility should engage in the remembrance of Allah and of the Truth which has been revealed (to them), and that they should not become like those to whom was given Revelation aforetime, but long ages passed over them and their hearts grew hard? For many among them are rebellious transgressors.

(227) Those who resist Allah and His Messenger will be humbled to dust, as were those before them: for We have already sent down Clear Signs. And the Unbelievers (will have) a humiliating Penalty,-

(228) Secret counsels are only (inspired) by the Evil One, in order that he may cause grief to the believers; but he cannot harm them in the least, except as Allah permits; and on Allah let the believers put their trust.

(229) It is He Who got out the Unbelievers among the People of the Book from their homes at the first gathering (of the forces). Little did ye think that they would get out: And they thought that their fortresses would defend them from Allah! But the (Wrath of) Allah came to them from quarters from which they little expected (it), and cast terror into their hearts, so that they destroyed their dwellings by their own hands and the hands of the believers, take warning, then, O ye with eyes (to see)!

(230) "Our Lord! Make us not a (test and) trial for the Unbelievers, but forgive us, our Lord! for Thou art the Exalted in Might, the Wise."